The present invention relates to an arbitration mechanism for awarding priority to one of a plurality of agents, in particular, a mechanism allowing the agent to dynamically determine the priority level to give to requests for access to a resource.
Where there is a single resource in a computing system whether the resource is a bus, an SRAM, a FIFO, etc., an arbitrator is required to control access to the resource from among a plurality of requesting agents. In accordance with many arbitration schemes, an arbiter assigns a priority level to each request made by the agents and decides which agents get access based on the assigned priority. Typically, requests with higher priority are given preferred access, preempting requests with lower priority. Agents making requests at the same priority level are given access in an equitable or round robin fashion. In these aforementioned arbitration schemes, however, the priority assigned to the agents is just a best guess as to what the current access needs of the agents are. As a result, agents whose access needs change over time (and thus requiring a higher priority) may be starved from access to the resource